lecture 37 Flashcards
what are lymphocytes
T and B cells
what cells cause autoimmunity and why
These lymphocytes can cause autoimmunity due to the random rearrangement of the germline sequence in the cells to make the BCR and TCR. this random rearrangement can make receptors that respond to self antigen.
what does SCID stand for
severe combined immunodeficiency.
whats SCID caused by
This is an example of a recessive X-linked chromosomal disorder, this means it is more common in males than it is in females. This SCID is where people affected by the disease lack functional T and B cells. Our innate immune system cannot make up for the lack of this immune response
how can we cure SCID
Bone marrow transplants can however fix this disorder.
whats an example of how a virus can interfere with the human immune system
One in the cell viruses can down regulate and or stop the expression of the MHC-1 protein receptors. Diseases like HIV do this.
what cells does HIV affect and how
What HIV also does is it targets and binds to CD4 TCRs. The HIV virus then enters the CD4 cell and multiplies within it.
how does HIV cause AIDS
HIV targets the CD4 cell. it then transcribes its genome into DNA. this DNA is then over-regulated which causes the cell to slowly die So infection of HIV leads to decreased number of CD4 cells. CD4 plays an important role in humoral and cytotoxic immune responses. As these cells are dead, we at a certain low threshold of CD4 are susceptible to everyday microbes and more able to get cancer.
how is decreased CD4 bad
When the CD4 T cell numbers drop as a result of the HIV virus, there won’t be enough B cells activated during an immune response, nor are enough T cells activated to become cytotoxic. The adaptive immune response thus begins to be less and less effective.
what causes an autoimmune disease
Caused by the adaptive immune system due to overactive lymphocytes
what prevents autoimmunity
Prevented by immune tolerance.
whats the site for T cell autoimmunity and where do we find it
The thymus is a site of autoimmunity as they screen the self reactive T and B cells.
In the thymus the autoreactive or impefect T cells are deleted. The thymus sits on top of the heart.
where does peripheral immune tolerance occur
in the lymph nodes
whats rheumatoid arthritis
In this the T and B cells react against target self antigens in the joint. Attacking these antigens and causing the athritis to take place. This generally occurs later in the life of a perosn.
whats type one diabetes
This is a very specific autoimmunity where only select cells are targeted. In this specifically, the beta cells of the pancreas are targeted by autoimmune response. The other cells within the pancreas are thus unaffected.
